1. Field of the Invention
The present invention relates to an impeller for a pump; and more particularly relates to an impeller for an axial pump.
2. Brief Description of Related Art
As one skilled in the art would appreciate, the main parts of any pump are the driver, impeller, and casing. The driver provides the energy for pumping, the impeller imparts the kinetic energy from the driver into the fluid, and the casing guides the fluid to its intended path.
The driver is usually an electric motor or an engine which converts electric or chemical energy into rotational kinetic energy. By way of example, the driver will be described and illustrated as a brushed DC electric motor although it does not have to be for the invention to be useful. The motor is comprised of three main parts; a static element—the stator, a rotating element—the rotor, and a means to transmit energy—the shaft.
The motor works by running an electric current through coils of wire wrapped in a particular arrangement around the rotor. The current generates a magnetic field perpendicular to the magnetic axis fields in place due to permanent magnets which are affixed to the stator. The interaction of these fields creates a torque on the rotor which causes it to rotate. Running axially through the center of the rotor is the shaft onto which the pump's impeller is mounted.
There are three general categories of pump impellers; axial, semi-axial, and radial. In an axial impeller the radial velocity of the fluid is negligible and the pumping action occurs parallel to the axis of the motor shaft. In a semi-axial pump design the impeller has both radial and axial curvature and the radial component of the fluid velocity is no longer negligible. In a radial impeller the flow is almost entirely radial and the axial component of the fluid velocity is negligible.